The FastFire III offers upgraded features such as windage and elevation adjustments that dont require a special tool; a convenient power button with three levels of brightness and an automatic brightness setting and battery access on the top of the sight making it easier to change batteries. Weve also added a low battery warning indicator and see-through protective cap.Ideally suited for use on pistols and AR-15s where fast target acquisition is desired, the FastFire red dot sight will also match up well with carbines, lever guns and shotguns. The FastFire III is ruggedly designed, impervious to the elements and will hold up to years of punishing recoil. Youll find a wide selection of mounts for either model that will fit on most popular shooting platforms.